Multicomponent decellularized extracellular matrix of caprine small intestine submucosa based bioactive hydrogel promoting full-thickness burn wound healing in rabbits.

Effective treatment for full-thickness burn wounds has remained challenging for clinicians. Among various strategies, extracellular gel-based dressing materials have gained attention to promote effective and rapid wound healing. These gel-based materials are porous and have antioxidant, antibacterial, hydrophilic, biodegradation, and biocompatible properties and hence can be used to alleviate burn wound healing. In concurrence with these findings, the present study evaluates thermo-responsive and self-assembled decellularized extracellular matrix (ECM) of caprine small intestine submucosa (DG-SIS) gel-based dressing material for burn wound healing. To expedite healing and efficiently tackle excessive free radicals and bioburden at the burn wound site, DG-SIS gel is fortified with antibacterial components (zinc oxide nanoparticles; ZnO) and a potent antioxidant agent (Vitamin-C;Vt-C). ZnO- and Vt-C-enriched DG-SIS (DG-SIS/ZnO/Vt-C) gels significantly increased the antioxidant and antibacterial activity of the therapeutic hydrogel. Additionally, the fabricated DG-SIS/ZnO/Vt-C bioactive gel resulted in significant full-thickness burn wound contraction (97.75 % in 14 days), a lower inflammatory effect, and enhanced angiogenesis with the highest collagen synthesis (1.22 µg/mg in 14 days) at the wound site. The outcomes from this study demonstrate a synergistic effect of ZnO/Vt-C in the bioactive gel as an effective and inexpensive therapeutic approach for full-thickness burn wound treatment.

Meropenem loaded 4-arm-polyethylene-succinimidyl-carboxymethyl ester and hyaluronic acid based bacterial resistant hydrogel.

Developing an ideal vitreous substitute/implant is a current challenge. Moreover, implants (e.g., heart valves and vitreous substitutes), are associated with a high risk of bacterial infection when it comes in contact with cells at implant site. Due to infection, many implants fail, and the patient requires immediate surgery and suffers from post-operative problems. To overcome these problems in vitreous implants, we developed a bacterial resistant vitreous implant, where meropenem (Mer), an antibiotic, has been incorporated in a hydrogel prepared by crosslinking HA (deacetylated sodium hyaluronate) with 4-arm-polyethylene-succinimidyl-carboxymethyl-ester (PESCE). The HA-PESCE hydrogel may serve as a suitable artificial vitreous substitute (AVS). The pre-gel solutions of HA-PESCE without drug and with the drug are injectable through a 22 G needle, and the gel formation occurred in approx. 3 min: it indicates its suitability for in-situ gelation through vitrectomy surgery. The HA-PESCE hydrogel depicted desired biocompatibility, transparency (>90 %), water content (96 %) and sufficient viscoelasticity (G' >100 Pa) calculated after 1 month in-vitro, which are suitable for vitreous substitute. The HA-Mer-PESCE hydrogel showed improved biocompatibility, suitable transparency (>90 %), high water content (96 %), and suitable viscoelasticity (G' >100 Pa) calculated after 1 month in-vitro, which are suitable for vitreous substitute. Further, hydrogel strongly inhibits the growth of bacteria E.coli and S.aureus. The drug loaded hydrogel showed sustained in-vitro drug release by the Fickian diffusion-mediated process (by Korsmeyer-Peppas and Peppas Sahlin model). Thus, the developed hydrogel may be used as a potential bacterial resistant AVS.

Nanoceria laden decellularized extracellular matrix-based curcumin releasing nanoemulgel system for full-thickness wound healing.

Decellularized extracellular matrix (ECM) has been widely used for wound healing. But, ECM failed to integrate tissue and restore the tissue function properly, when elevated levels of free radicals and biofilm formation occur at the wound site. Here, nanoemulgel systems were fabricated, considering the combinatorial approach of nanotechnology (nanoceria and curcumin nanoemulsion) and ECM gel of goat small intestine submucosa. The curcumin was encapsulated in the nanoemulgel system to enhance bioavailability in terms of antibacterial, antioxidant, sustained release and permeation at the wound site. Nanoceria was also incorporated to enhance the antibacterial, antioxidant and wound healing properties of the fabricated nanoemulgel formulation. All the formulations were porous, hydrophilic, biodegradable, antioxidant, antibacterial, hemocompatible, biocompatible, and showed enhanced wound healing rate. The formulation (DG-SIS/Ce/NC) showed the highest free radicals scavenging capacity and antibacterial property with prolonged curcumin release (62.9% in 96 h), skin permeability (79.7% in 96 h); showed better cell growth under normal and oxidative-stressed conditions: it also showed full-thickness wound contraction (97.33% in 14 days) with highest collagen synthesis at the wound site (1.61 µg/mg in 14 days). The outcomes of this study suggested that the formulation (DG-SIS/Ce/NC) can be a potential nanoemulgel system for full-thickness wound healing application.

Development of decellularization protocol for caprine small intestine submucosa as a biomaterial.

Decellularized animal tissues have been proven to be promising biomaterials for various tissue engineering (TE) applications. Among various animal tissues, small intestine submucosa (SIS) has gained attention of many researchers due to its easy availability from the abattoir waste, excellent physicochemical and biological characteristics of a good biomaterial. In this study, Caprine SIS was decellularized to get decellularized caprine SIS (DG-SIS). For decellularization, several physical, chemical and enzymatic protocols have been described in the literature. To optimize the decellularization of caprine SIS, several decellularization protocol (DP), including an in-house developed by us, had been attempted, and effect of the different DPs on the obtained DG-SIS were assessed in terms of decellularization, physiochemical and biological properties. All the DPs differ in terms of decellularization, but three DPs where ionic detergent like sodium dodecyl sulphate (SDS) has been used, largely affect the native composition (e.g. glycosaminoglycans (GAGs)), biological properties and other physiochemical properties of the G-SIS as compared to the DP that uses hypertonic solution of potassium iodide (KI) and non-ionic detergent (TritonX-100). The obtained DG-SISs were fibrous, hemocompatible, biocompatible, hydrophilic, biodegradable and exhibited significant antibacterial activity. Therefore, the DG-SIS will be a prospective biomaterial for TE applications.

Curcumin in decellularized goat small intestine submucosa for wound healing and skin tissue engineering.

Biomaterials derived from extracellular matrices (ECMs) were extensively used for skin tissue engineering and wound healing. ECM is a complex network of biomolecules (e.g., proteins), which provide organizational support to cells for growth. Thus, ECM could be an ideal biomaterial for fabricating the scaffold. However, oxidative stress and biofilm formation at the wound site remains a major challenge that could be neutralized using herbal ingredients (e.g., curcumin). In this study, ECM was extracted from the biowaste of the goat abattoir by using decellularization. The goat small intestine submucosa (G-SIS) is decellularized to obtain the decellularized G-SIS (DG-SIS) and curcumin (in different concentrations) was incorporated in the DG-SIS to fabricate curcumin-embedded DG-SIS scaffolds. Changes brought by increasing the concentrations of the curcumin in DG-SIS were observed in various properties, including free radical scavenging and antibacterial properties. Results depicted that the scaffolds are porous, biodegradable, biocompatible, antibacterial, and hydrophilic and showed sustained release of curcumin. Besides, it showed free radicals scavenging property. The porosity and hydrophilicity of the scaffolds were decreased with an increase in the curcumin content. However, biodegradability, free radical scavenging, biocompatibility, and antibacterial properties of the scaffolds increased with an increase in the curcumin content. The DG-SIS scaffold containing 1 wt % of curcumin may be a potential biomaterial for wound-healing and skin tissue engineering.

A highly transparent tri-polymer complexin situhydrogel of HA, collagen and four-arm-PEG as potential vitreous substitute.

There is a requirement of removal and replacement of vitreous for various ophthalmic diseases, e.g. retinopathy and retinal detachment. Clinical tamponades, e.g. silicone oil and fluorinated gases are used but limited due to their toxicity and some complications. A lot of polymer-based materials have been tested and proposed as vitreous substitute, but till date, there is no ideal vitreous substitute available. Thus, it requires to develop an improved vitreous substitute which will be highly suitable for vitreous replacement. We have developed tri-polymer complexin situhydrogels by crosslinking among hyaluronic acid (HA), collagen (Coll) and four-arm-polyethylene glycol (PEG). All the developed hydrogels are biocompatible with NIH 3T3 mouse fibroblast cells, having pH in the range 7-7.44 and refractive index in the range 1.333-1.345. The developed hydrogels are highly transparent, showing transmittance >97%. FTIR study shows that the hydrogel was crosslinked by amide bond formation between HA and PEG, and between Coll and PEG. The rheological study shows that all the developed hydrogels exhibit viscoelastic behavior and all the hydrogels have storage modulus values (>100 pa) which is greater than loss modulus values-indicating sufficient elasticity for vitreous application. The elastic nature of the hydrogel increases with the increase in PEG concentration. The gel is formed in between 2 and 3 min-indicating its applicationin situ. The viscosity of the developed hydrogels shows shear thinning behavior. The pre-gel solution of the hydrogel is injectable through a 22 G needle-indicating its applicationin situthrough vitrectomy surgery. All the hydrogels are hydrophilic and have water content of 96% approximately. Thus, the results show the positive properties for its application as a potential vitreous substitute.

Biomatrix from goat-waste in sponge/gel/powder form for tissue engineering and synergistic effect of nanoceria.

For tissue engineering (TE), decellularized matrices gained huge potential as they consist of natural biomolecules which help in cell attachment and proliferation. Among various animal tissues, goat tissue has gained least attention in spite of the fact that goat tissue is less susceptible to disease transmission as compared to cadaveric porcine and bovine tissue. In this study, goat small intestine submucosa (G-SIS) was isolated from goat small intestine (G-SI), a waste from goat-slaughterhouse, and decellularized to obtain decellularized G-SIS (DG-SIS) biomatrix in the form of powder, gel and sponge form, so that it can be used for healing various types of wounds. Further, nanoceria (NC), owing to its free radical scavenging, anti-inflammatory, antibacterial and angiogenic properties, was incorporated in the DG-SIS in to fabricate DG-SIS/NC nanobiocomposite scaffold, which may exhibit synergistic effects to accelerate tissue regeneration. The scaffolds were found to be hydrophilic, biodegradable, haemocompatible, biocompatible, antibacterial and showed free radical scavenging capability. The scaffold containing NC concentration (500 µg ml-1) depicted highest cell (fibroblast cells) adhesion, MTT activity and free radical scavenging as compared to the DG-SIS and other nanobiocomposite scaffolds. Thus, DG-SIS/NC3 (NC with concentration 500 µg ml-1) scaffold could be a potential scaffold biomaterial for skin TE application.

Vitreous substitutes: An overview of the properties, importance, and development.

Vitreous or vitreous humor is a complex transparent gel that fills the space between the lens and retina of an eye and acts as a transparent medium that allows light to pass through it to reach the photoreceptor layer (retina) of the eye. The vitreous humor is removed in ocular surgery (vitrectomy) for pathologies like retinal detachment, macular hole, diabetes-related vitreous hemorrhage detachment, and ocular trauma. Since the vitreous is not actively regenerated or replenished, there is a need for a vitreous substitute to fill the vitreous cavity to provide a temporary or permanent tamponade to the retina following some vitreoretinal surgeries. An ideal vitreous substitute could probably be left inside the eye forever. The vitreous humor is transparent, biocompatible, viscoelastic and highly hydrophilic; polymeric hydrogels with these properties can be a potential candidate to be used as vitreous substitutes. To meet the tremendous demand for the vitreous substitute, many scientists all over the world have developed various kinds of vitreous substitutes or tamponade agent. Vitreous substitutes, whatsoever developed till date, are associated with several advantages and disadvantages, and there is no ideal vitreous substitute available till date. This review highlights the polymer-based vitreous substitutes developed so far, along with their advantages and limitations. The gas-based and oil-based substitutes have also been discussed but very briefly.

Gelatin-polycaprolactone-nanohydroxyapatite electrospun nanocomposite scaffold for bone tissue engineering.

Bone injuries and fractures generally take a long period to heal itself. To address this problem, bone tissue engineering (BTE) has gained significant research impetus. Among the several techniques used for scaffold fabrication, electrospinning ought to be the most promising technique for the development of the nanostructured scaffolds. The present study was carried out to fabricate an electrospun nanocomposite scaffold for BTE by using gelatin, polycaprolactone (PCL), and nanohydroxyapatite (nHAp). To prepare Gelatin-PCL-nHAp nanocomposite scaffold: Gelatin-PCL blend was electrospun and then treated with nHAp (1 wt%) for different time periods. The fabricated nanocomposite scaffold was analysed by field emission scanning electron microscopy (FESEM) to determine the fiber diameter and evaluate the fiber morphology. The Gelatin-PCL-nHAp nanocomposite scaffold-20 min exhibited the average fiber diameter of 615±269 nm and average pore size 4.7±1.04 µm, and also revealed the presence of nHAp particles over the Gelatin-PCL scaffold surface. Further, X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) spectroscopy and thermogravimetric (TG) analysis also indicated the deposition of nHAp over the Gelatin-PCL scaffold surface. MTT assay and DNA quantification showed good viability and significant proliferation of human osteoblasts on Gelatin-PCL-nHAp nanocomposite scaffold. Moreover, cell-scaffold constructs illustrated efficient cellular attachment and adequately spread cells, and it also depicts characteristic polygonal morphology of osteoblasts over the Gelatin-PCL-nHAp nanocomposite scaffold. Thus, the results of in-vitro analysis of electrospun nanocomposite scaffold suggest that the Gelatin-PCL-nHAp scaffold can be a potential candidate for BTE applications.

Gelatin-alginate-cerium oxide nanocomposite scaffold for bone regeneration.

Worldwide the number of bone damage/fracture, due to traumatic and accidental injuries, has been growing exponentially. Currently available treatments for bone repairing are slow, and often full functional recovery is not achieved. During slow healing process, free radicals are generated at fractured site, which causes further delay in healing process. To overcome these problems, bone tissue engineering (BTE) based approaches, i.e., polymeric scaffolds loaded with free radical scavenging capabilities, seem to be a potential alternative. Cerium oxide nanoparticles (nanoceria, NC) show very good free radical scavenging capabilities. In this study, NC was incorporated in gelatin-alginate (GA) scaffolds to obtain nanocomposite scaffolds (GA-NCs) by freeze drying. Further, the effect of varying nanoceria concentration on the physicochemical and biological properties of the nanocomposite scaffolds has been evaluated. Field emission scanning electron microscopy (FESEM) images of the scaffolds revealed presence of interconnected pores. Furthermore, incorporation of NC has increased the mechanical properties, bio-mineralization, and decreased the swelling and in-vitro weight loss of the scaffolds. Additionally, GA-NCs depicts competent cell attachment, proliferation and viability. The results for osteogenic differentiation studies (i.e. ALP activity, RunX2 and osteocalcin expression) have indicated that GA-NCs scaffolds hold potential to assist differentiation of mesenchymal stem cells (MSCs) to osteoblast. Finally, the results for free radical scavenging functionality demonstrate that GA-NCs are capable of reducing free radicals. Thus, it could be stated that NC incorporated GA nanocomposite scaffold has vital importance for applications in bone tissue-engineering in future regenerative therapies.

Development of a nanocomposite scaffold of gelatin-alginate-graphene oxide for bone tissue engineering.

Bone damage, due to congenital defects, trauma and sports-related injuries, has become a foremost health problem all over the world. The present study involves fabrication of a nanocomposite scaffold of graphene oxide (GO), gelatin and alginate, with an aim of enhancing bone regeneration. The effect of varying concentration of GO on the scaffold properties was also determined. The incorporation of GO enhanced the compressive strength of the nanocomposite scaffolds significantly compared to the gelatin-alginate (GA) scaffold which is without GO. High % swelling (~700%) of the nanocomposite scaffold indicates its high hydrophilicity, which is suitable for tissue engineering. Slow biodegradation (~30% in 28 days) indicates its suitability for bone regeneration. In vitro studies, by seeding MG-63 cells over the nanocomposite scaffolds, revealed an enhancement in cell attachment and proliferation as compared to the GA scaffold: this indicates the positive effect of the GO on the scaffold properties which, in turn, can enhance bone regeneration. Cell differentiation studies, with the mesenchymal stem cells seeded scaffolds, revealed higher expression of osteoblast transcription factors (Runx2 and Osteocalcin) and alkaline phosphatase activity-indicating the scaffold to be a good osteoinductive material. Thus, the nanocomposite scaffold will be a potential scaffold for bone tissue engineering.